Controlling translocation through nanopores with fluid walls

Abstract

Improved resolution and detection of nanoparticles are achieved when a nanopore connecting liquid compartments in a device running on the Coulter principle is provided with fluid coatings such as lipid walls. Fluid lipid walls are made of a lipid bilayer, and preferably include lipid anchored mobile ligands as part of the lipid bilayer. By varying the nature and concentration of the mobile ligand in the lipid bilayer, multifunctional coatings of lipids are provided.

What is claimed is: 
     
       1. A method of detecting, quantifying, or characterizing a biomolecule, collection of biomolecules, or particles, comprising:
 providing a transit path for biomolecules or particles to pass through a nanopore from a first liquid compartment to a second liquid compartment, wherein the first and second liquid compartments contain electrodes disposed to measure voltage difference, current flow, or resistance between the first and second liquid compartments; and 
 measuring voltage difference, current flow, or resistance between the first and second liquid compartments over time as individual biomolecules pass through the nanopore; 
 wherein the nanopore is a passageway through a substrate, the passageway being lined with a fluid wall, wherein the fluid wall comprises a monolayer or a bilayer, the monolayer or the bilayer comprising a lipid anchored ligand and an amphipathic molecule, a surfactant, or a detergent. 
 
     
     
       2. The method according to  claim 1 , wherein the monolayer or the bilayer comprises the amphipathic molecule. 
     
     
       3. The method according to  claim 1 , wherein the fluid wall comprises the bilayer. 
     
     
       4. The method according to  claim 1 , wherein the monolayer or the bilayer comprises the surfactant or the detergent. 
     
     
       5. The method according to  claim 1 , wherein the nanopore is characterized by a nominal width perpendicular to the transit path that is about 1.5 to about 50 times the dimension of the biomolecule or particle and wherein the length of the nanopore parallel to the transit path is one to five times its nominal width. 
     
     
       6. The method according to  claim 1 , wherein the fluid wall comprises the monolayer. 
     
     
       7. The method according to  claim 1 , wherein the lipid anchored ligand comprises an antibody. 
     
     
       8. The method according to  claim 1 , wherein the nanopore has a nominal width of 10 to 200 nanometers. 
     
     
       9. The method according to  claim 1 , wherein the nanopore has a nominal width of 20 to 30 nanometers. 
     
     
       10. The method according to  claim 1 , wherein the biomolecule comprises a protein or protein aggregate. 
     
     
       11. The method according to  claim 1 , wherein the biomolecule comprises a nucleic acid. 
     
     
       12. The method according to  claim 1 , wherein the biomolecule comprises an antibody. 
     
     
       13. The method according to  claim 10 , wherein the protein is an amyloid β protein. 
     
     
       14. The method according to  claim 1 , wherein the lipid anchored ligand comprises a lipid molecule comprising a ligand, wherein the lipid molecule is bound within the monolayer or the bilayer and the ligand is biotin, cholesterol, sulfonamide, nickel, an antibody, or a non-antibody protein. 
     
     
       15. The method according to  claim 13 , wherein the ligand is a non-antibody protein comprising a thiol group, a maleimide group, or a N-hydroxysuccimide (NHS) ester group. 
     
     
       16. The method according to  claim 1 , wherein the monolayer or the bilayer comprises the amphipathic molecule, the amphipathic molecule being a phospholipid or a sphingolipid. 
     
     
       17. A method of measuring a translocation time, ligand affinity, charge, volume, shape, size, or other characteristic of a biomolecule, the method comprising:
 detecting and measuring a change in conductivity, resistivity, resistance, conductance, current flow, voltage, or other electrical parameter measured between two liquid compartments separated by and fluidically coupled through a synthetic nanopore upon translocation of the biomolecule from one liquid compartment through the synthetic nanopore to the other liquid compartment; and 
 deriving the biomolecule characteristic from the measured electrical parameter, 
 wherein the synthetic nanopore comprises a passageway lined with a fluid wall, wherein the fluid wall comprises a monolayer or a bilayer, the monolayer or the bilayer comprising a lipid anchored ligand and an amphipathic molecule, a surfactant, or a detergent. 
 
     
     
       18. A device for measuring a parameter of a biomolecule using the Coulter principle, the device comprising:
 a first liquid compartment and a second liquid compartment; 
 a synthetic nanopore disposed between and providing a fluid path between the first liquid compartment and second liquid compartment, and defining a fluid flow direction from the first liquid compartment to the second liquid compartment; 
 a first electrode in the first liquid compartment and a second electrode in the second liquid compartment; and 
 means for controlling the first electrode and second electrode to measure resistance, voltage difference, or current flow between the first and second electrodes, wherein the synthetic nanopore is a passageway between the first liquid compartment and second liquid compartment lined with a fluid wall, and wherein the passageway lined with the fluid wall provides a transit path for the biomolecule to pass from the first liquid compartment to the second liquid compartment, wherein the fluid wall comprises a monolayer or a bilayer, the monolayer or the bilayer comprising a lipid achnored ligand and an amphipathic molecule, a surfactant, or a detergent. 
 
     
     
       19. The device according to  claim 18 , wherein a dimension of the synthetic nanopore perpendicular to the fluid flow direction is 10 to 100 nanometers. 
     
     
       20. The device according to  claim 18 , wherein the synthetic nanopore has a length in the fluid flow direction of 10 to 100 nanometers.